7.2.3.2
Solidly earthed systems
GUID-ED1D9B07-3EAF-436C-A6EA-044455DC168E v1
illustrates how the distance protection ZRWPDIS protects a
110kV overhead transmission line. The earthing considered is solidly earthed
system.
Out of the six distance protection zones, only the zone 1, zone 2 and zone 3 are
considered in this example. Zones 4, 5 and 6 can be set on similar lines depending
on the application they are being used.
All the settings for impedance are in Ohms Primary.
Z<
A
B
C
Line 1
Line 2
IEC15000385-1-en.vsdx
IEC15000385 V1 EN-US
Figure 43:
Considered single line diagram
Table 16:
System Data
Parameter
Value
System Voltage
110kV
System Frequency
16.7Hz
Full load
50MVA
Short time maximum Power
250% of Full load
Minimum operating voltage
90% of rated voltage
PT Ratio
110kV/110V
CT Ratio
600/1A
Line length A-B
50km
Line length B-C
100km
Positive sequence impedance of line
0.097 + j0.112 Ohm/km = 0.1481 ∟ 49.3°
Ohm/km
Zero sequence impedance of line
0.151 + j0.298 Ohm/km = 0.334 ∟ 63.13°
Ohm/km
Arc resistance
2 Ohm
Tower footing resistance
10 Ohm
General
GUID-FB2EC166-F828-4760-93EC-D5FCDBA39657 v1
Common base IED values for primary current (
IBase
) and primary voltage (
UBase
)
are set in a Global base values for settings function GBASVAL.
GlobalBaseSel
: It is used to select a GBASVAL function for reference of base
values.
IBase
: Sets the base current in primary ampere. This is 50MVA/110kV = 454.54A.
1MRK 506 375-UEN A
Section 7
Impedance protection
Railway application RER670 2.2 IEC
143
Application manual
Summary of Contents for RELION RER670
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